From a physical point of view the term "brilliance" comprises several distinct optical processes in diamond:
- External brilliance:
luster, produced by the reflection of light on the surface of the facets.
- Internal brilliance:
Refraction and total reflection of light on the pavilion facets.
- Dispersive brilliance:
Splitting or scattering of light into its spectral colors = the dispersion which evokes the "fire" or "life" in a brilliant.
- Scintillation brilliance:
The "sparkle" of the stone when moved, caused by light reflections of the light source.